System and method of operating an antenna in MIMO and beamforming modes

Abstract

A system and method of operating an antenna in a beamforming mode or a multiple-input multiple-output (MIMO) mode. The method includes activating a first group of antenna elements to operate the antenna in the beamforming mode; and activating a second group of antenna elements to operate the antenna in the MIMO mode. The distance between adjacent antenna elements of the first group may be a half-wavelength at the antenna operating frequency, and the distance between adjacent antenna elements of the second group may be greater than a half-wavelength. If the antenna elements are configured as an array, the first group may include all of the elements of the array, and the second group may include only the elements in every other column of the array. The operation of the antenna in either the beamforming mode or the MIMO mode may be based on the RF environment in which subscriber units reside.

1. A method of operating an antenna in first and second modes, comprising:
 activating a first group of antenna elements of said antenna to operate said antenna in said first mode; and 
 activating a second group of antenna elements of said antenna to operate said antenna in said second mode, wherein said first group of antenna elements is different than said second group of antenna elements, 
 wherein said antenna elements of said antenna are configured in a square or rectangular array, and wherein said second group consists of antenna elements in every other column of said square or rectangular array. 
 
   
   
     2. The method of  claim 1 , wherein said first mode comprises a beamforming mode. 
   
   
     3. The method of  claim 2 , wherein said first group of said antenna elements comprises all antenna elements of said antenna. 
   
   
     4. The method of  claim 3 , wherein a distance of respective adjacent antenna elements is a half-wavelength at an approximate central frequency of operation of said antenna. 
   
   
     5. The method of  claim 1 , wherein said second mode comprises a multiple-input multiple-output (MIMO) mode. 
   
   
     6. The method of  claim 5 , wherein said second group of said antenna elements comprises only a subset of all antenna elements of said antenna. 
   
   
     7. The method of  claim 6 , wherein a distance of respective adjacent antenna elements in said subset is greater than a half-wavelength at an approximate central frequency of operation of said antenna. 
   
   
     8. The method of  claim 1 , wherein said first mode comprises a beamforming mode, wherein said first group of said antenna elements comprises all antenna elements of said antenna, and wherein a distance of respective adjacent antenna elements is a half-wavelength at an approximate central frequency of said operation of said antenna; and wherein said second mode comprises a MIMO mode, wherein said second group of said antenna elements comprises only a subset of said antenna elements of said antenna, and wherein a distance of respective adjacent antenna elements in said subset is greater than a half-wavelength at said approximate central frequency of said operation of said antenna. 
   
   
     9. The method of  claim 1 , further comprising:
 determining a quality factor of an RF environment in which one or more subscriber units (SU) reside; and 
 operating said antenna in either said first mode or said second mode based on said quality factor. 
 
   
   
     10. The method of  claim 1 , further comprising:
 receiving information regarding an RF environment in which one or more subscriber units (SU) reside; 
 determining a quality factor of said RF environment based on said received information; and 
 operating said antenna in either said first mode or said second mode based on said quality factor. 
 
   
   
     11. The method of  claim 10 , wherein receiving said information occurs within a first time slot; and wherein operating said antenna in either said first mode or said second mode based on said quality factor occurs within a second time slot subsequent to said first time slot. 
   
   
     12. A base transceiver station (BTS), comprising:
 an antenna; 
 an antenna excitation module adapted to operate said antenna in either a first antenna mode wherein a first group of antenna elements are activated, or in a second antenna mode wherein a second group of antenna elements are activated, wherein said first group of antenna elements is different than said second group of antenna elements; and 
 a controller adapted to instruct said antenna excitation module to operate said antenna in either said first antenna mode or said second antenna mode, 
 wherein said antenna elements of said antenna are configured in a square or rectangular array, and wherein said second group consists of antenna elements in every other column of said square or rectangular array. 
 
   
   
     13. The base transceiver station (BTS) of  claim 12 , wherein said first mode comprises a beamforming mode. 
   
   
     14. The base transceiver station (BTS) of  claim 12 , wherein said second mode comprises a multiple-input multiple-output (MIMO) mode. 
   
   
     15. The base transceiver station (BTS) of  claim 12 , wherein said first mode comprises a beamforming mode, and said second mode comprises a multiple-input multiple-output (MIMO) mode. 
   
   
     16. The base transceiver station (BTS) of  claim 12 , wherein said controller is adapted to:
 determine a quality factor of an RF environment in which one or more subscriber units (SU) reside; and 
 instruct said antenna excitation module to operate said antenna in either said first mode or said second mode based on said quality factor. 
 
   
   
     17. The base transceiver station (BTS) of  claim 12 , wherein said controller is adapted to:
 receive information regarding an RF environment in which one or more subscriber units (SU) reside; 
 determine a quality factor of said RF environment based on said received information; and 
 instruct said antenna excitation module to operate said antenna in either said first mode or said second mode based on said quality factor. 
 
   
   
     18. The base transceiver station (BTS) of  claim 17 , wherein said controller is adapted to:
 receive said information within a first time slot; and 
 instruct said antenna excitation module to operate said antenna in either said first mode or said second mode based on said quality factor in a second time slot subsequent to said first time slot. 
 
   
   
     19. The base transceiver station (BTS) of  claim 12 , wherein said controller is adapted to:
 receive information regarding an RF environment in which one or more subscriber units (SU) reside in a first time slot; 
 determine a quality factor of said RF environment based on said received information; 
 determine whether said quality factor is above a threshold level; and 
 instruct said antenna excitation module to operate said antenna in said first mode if said quality factor is above said threshold level; or 
 instruct said antenna excitation module to operate said antenna in said second mode if said quality factor is below said threshold level. 
 
   
   
     20. A wireless communication system, comprising:
 a network; and 
 one or more base transceiver station (BTS) coupled to said network, wherein at least one of said one or more base transceiver station (BTS) comprises:
 an antenna; 
 an antenna excitation module adapted to operate said antenna in either a first antenna mode wherein a first group of antenna elements are activated, or in a second antenna mode wherein a second group of antenna elements are activated, wherein said first group of antenna elements is different than said second group of antenna elements; and 
 a controller adapted to instruct said antenna excitation module to operate said antenna in either said first antenna mode or said second antenna mode, 
 
 wherein said antenna elements of said antenna are configured in a square or rectangular array, and wherein said second group consists of antenna elements in every other column of said square or rectangular array.